And, in particular, the question: Why would anyone think it a good idea to do a PhD dissertation on a topic in the history of philosophy? Here's a letter to prospective graduate students from Bob Pasnau at Colorado that tries to make a case in favour (pdf file).
Any thoughts? I wondered myself about the following paragraph. It might well be true of programmes and departments in the US, but I was less convinced that it is true of the UK, in part because of differences in the way that graduate places are assigned and also because often the division of labour between philosophy and other cognate departments may be different.
First and foremost, it is both easier to get into a good PhD program if you focus on history, and easier to get a job. Almost every PhD program wants graduate students in history, and every department, no matter how small, needs faculty to teach the historical core. There are, however, many fewer candidates for these positions. Even the very top PhD programs in the history of philosophy receive only an handful of candidates seeking to study in those areas, and it is not unusual for there to be roughly as many jobs in the history of philosophy as there are plausible candidates.
He goes on to point out (rightly) that a dissertation in this history of philosophy does not shackle you to historical study for the rest of your career. And there are other arguments that I think are more positive, including the observation that historians of philosophy tend to wield the principle of charity and do the best for the people they read, while it is often the case that in dealing with our contemporaries we are inclined to offer the least charitable interpretation of what they write...